The present invention relates to a liquid cooling system, especially one which is suitable for cooling the lubricating oil of an internal combustion engine.
German Patent Application No. DE 296 22 191 discloses a plate-type heat exchanger which is comprised of a plurality of heat exchanger plates. The heat exchanger plates are formed by stacked deep-drawn troughs each having a circumferential marginal rim. The flow troughs have extensions on which surfaces of adjacent troughs are sealingly supported. In the area of temporary extensions which connect the troughs alternately to one another, openings are formed fore the heat-exchanging media. Turbulence vanes are placed in the troughs in contact on both sides with the stacked heat exchanger plates through tabs which are disposed in mutually offset rows, formed between parallel slots, and bent out of the plane of the plates in an undulating manner. The heat exchanger plates have openings associated with one another in pairs for the heat-exchanging media. The openings are arranged such that they are situated in the area of the extensions. Since the openings are smaller than the extensions, a sealing separation of the heat-exchanging media from one another is achieved.
By arranging the openings for the passage of the medium to be cooled and the openings for the cooling medium in the plates of the cooler, the effective heat exchange area of the plate heat exchanger is reduced. In order, however, to achieve good efficiency in the plate heat exchanger, the size of the plate heat exchanger is increased, so that it becomes bulkier. Since the openings must not have less than a minimum diameter for Theological reasons, the arrangement of the openings in the plates of the cooler determines the minimum size of the plate heat exchanger.
It is known that cooling elements can be built into a housing, and that connections for the coolant must be separate from the connections of the medium to be cooled, so as to cause no mixing of the two media with one another. For this purpose the connections of the two media are spatially separated and displaced from each other, and usually are contained in different components. In other embodiments of connections, the connections are passed through the housing and affixed with nuts.
These designs, however, are complicated to assemble, since the connections must be individually attached and connected. Furthermore, additional lines are needed, which require space and are considerably difficult to assemble. Despite the efforts of the prior art, there has remained a need for a liquid cooling system which requires little space and which can be assembled quickly and easily.
It is therefore the object of the invention to provide a liquid cooling system which is compact and requires little space for installation.
It is also an object of the invention to provide a liquid cooling system which can be assembled easily and quickly.
These and other objects of the invention are achieved in accordance with the present invention by providing a liquid cooling system comprising a housing defining an interior volume, a housing cover for closing the housing, and a liquid cooler disposed in the interior volume; the housing having at least one inlet for liquid to be cooled opening into the housing interior volume, at least one outlet for cooled liquid, at least one coolant inlet, and at least one coolant outlet; the liquid cooler being comprised of stacked cooler plates each forming a liquid space and a coolant space sealingly separated from one another, a return passage for the cooled liquid arranged in the liquid cooler such that it passes through all cooling plates; each liquid space having an opening in fluid communication with the inlet for liquid to be cooled and another opening in fluid communication with the outlet for cooled liquid, and the coolant spaces being in fluid communication through respective openings in a bottom plate of the liquid cooler with the coolant inlet and with the coolant outlet; wherein the bottom plate of the liquid cooler sealingly contacts the housing such that an inner area space and an outer area space completely surrounding the inner area are formed between the bottom plate and the housing and are separated from the housing interior volume; the inner area space connecting the return passage to the outlet for cooled liquid, and the outer area space connecting the coolant spaces to the coolant inlet and to the coolant outlet.
The liquid cooling system of the invention is advantageously suitable for cooling liquids such as water, oil or gasoline, and at the same time it requires little space for installation. Furthermore, the liquid cooling system of the invention can be assembled easily and quickly. For this purpose the liquid cooling system has a housing comprising a housing volume. The housing has at least one liquid inlet, one liquid outlet, a coolant inlet and a coolant outlet. These inlets and outlets can have any desired shape, such as round, oval, kidney-shaped, square, rectangular or polygonal. Also, they can vary in shape between the inlet and outlet, as for example round to oval or angular to round. They are connected to the respective lines of the corresponding circuits. Liquids, such as oil or water, for example, can be used, optionally containing additives. The housing can be an independent component into which only components of the liquid cooling system are integrated, or it also can be formed by other components. In this regard, it is possible for the housing to be formed as part of some other component of an internal combustion engine. Another variant for the construction of the housing it to configure a liquid tank, especially an oil pan, such that the housing functions are fulfilled.
The liquid cooling system furthermore comprises a housing cover and a liquid cooler. The housing cover is designed so that it can be sealingly attached to the housing. For this purpose the cover can. be fastened to the housing, for example, with screws, clips, or a bayonet lock. The housing cover, however, can also contain a screw thread which is screwed into the housing. If the housing is formed of other components as described above, the cover is sealingly joined to that component. The liquid cooler is constructed as a cooling module and is formed by individual cooler plates which are stacked and sealingly joined to one another. For example, the cooler plates can be soldered or adhesively bonded to one another. A liquid space is sealingly separated from a coolant space by the assembled cooler plates. Since a plurality of cooler plates are stacked one on top of another, a coolant space and a liquid space alternate with one another. These spaces are sealingly separated from one another so that no mixing of the coolant from the coolant space with liquid from the liquid space can occur. Furthermore, the liquid space has openings which allow the liquid to flow into and out of the liquid space. These openings communicate with the liquid inlet and the liquid outlet, but no separate component is provided for connecting the openings with the inlets and outlets. The liquid cooling system has only one connection route from the liquid inlet to the openings and from the openings to the liquid outlet. This connection route is defined by components already present, such as the housing with the liquid cooler.
The coolant space has openings in a bottom plate, which communicate with the coolant inlet and the coolant outlet through an intermediate space. The intermediate space, which is formed by the housing and the bottom plate, is subdivided into an inner area and an outer area. The outer area completely surrounds the inner area. These areas are sealed from one another and from the housing volume, so that the coolant can pass only from the bottom plate into the coolant inlet and out of it and not mix with the liquid to be cooled. If desired, gaskets may be used. Appropriate means are provided to prevent the coolant from passing directly from the coolant inlet to the coolant outlet. This can be accomplished by a structural configuration of the housing or bottom plate.
In the liquid cooler there is a return passage through which conducts the cooled liquid to the liquid outlet. The return passage passes through each cooler plate and is configured so that no liquid can pass in or out in the area of the cooler plates. For this purpose the return passage can be constituted by a separate component which is inserted into the liquid cooler or it can form a continuous, sealed duct through an appropriate configuration of the cooler plates, into which neither the uncooled liquid nor the coolant can enter. This return passage opens into an inner area adjoining the liquid outlet.
One advantageous embodiment of the invention envisions the use of sealing rings, such as O-rings, for example, to seal the inner area from the outer area. Furthermore, sealing rings can be used for sealing the outer area from the housing volume. The sealing rings can be composed of synthetic resin materials, especially elastomers. However, sealing rings of soft metals can also be used. These sealing rings are placed in recesses in the housing or bottom plate, and after the liquid cooler is installed in the housing, they seal the different areas from one another. For this purpose 2 seals are to be provided for the separation of 3 sides.
One particular embodiment of the invention involves the use of a nipple for fastening the liquid cooler in the housing. For this purpose the nipple is inserted into the liquid outlet and can be affixed with a snap fastening, for example. The nipple can be fixedly attached to the liquid cooler, especially by soldering. The connection between the nipple and the liquid cooler can be made at the bottom plate. Alternatively, however, the nipple can also be extended centrally through the liquid cooler and rest against a cover plate, with the liquid cooler clamped between the nipple and the housing. A fixed connection of the nipple inserted into the liquid cooler can likewise be provided.
An advantageous embodiment of the invention envisions a thread on the nipple, by which the nipple can be screwed into the liquid outlet and thus provide a connection to the housing. For this purpose the counter thread is to be provided in the housing, especially in the liquid outlet. The thread of the nipple can also be a self-cutting thread, so that no thread needs to be provided in the liquid outlet. With this way of fastening the liquid cooler in the housing, an optimum sealing of the return passage to the liquid outlet is achieved, and with the central application of force by the threaded nipple, an optimum sealing of the inner and outer areas is assured.
It is advantageous to provide ribs in the housing to form flow channels for the media passed through the liquid cooler. These ribs are distributed about the circumference and produce a resistance to flow by which the media follow their course through the liquid cooler. A certain bypass leakage of the liquid between the housing and the liquid cooler, which can be defined according to the tolerances of the liquid cooler and the ribs, does not impair the cooling function.
An especially advantageous embodiment of the liquid cooling system is the combination of the liquid cooler with a filter element. With this design, connecting lines to carry the liquid from the liquid cooler into a filter can be omitted, as well as the filter housing and filter cover. The filter element separates the raw liquid side from the clean liquid side. The filter element is disposed, for example, on the cover plate, with a filter element receptacle being provided to receive the filter element and seal the raw liquid side from the clean liquid side. In this embodiment of the liquid cooler, the housing cover is joined not to the liquid cooler but to the filter element. The cooled and filtered liquid is conducted into the return passage and returned to the liquid circuit through the liquid outlet.
It is advantageous to configure the filter element as a replaceable cartridge so that the liquid cooler system can remain where it is installed, and the filter element can be replaced simply by removing the housing cover.
An advantageous embodiment of the liquid cooling system is to be seen in a cylindrical design. In this embodiment a good ratio of cooling surface and filter surface to the space occupied by the device is achieved.
According to another embodiment of the invention, a central tube is provided to support the filter element in a liquid cooling system having a cylindrical design. This central tube can have holes or slots so that the liquid can flow out through them. Also, the central tube can be formed on the housing cover and, by placing the housing cover on the housing it can be brought into an internal space formed by the filter element on the clean liquid side. This central tube furthermore has a sealing seat on which the filter element is supported and thus sealingly separates the clean liquid side from the raw liquid side. The central tube, however, can also be attached to the cover plate, so that the housing cover does not need to be inserted into the filter element during assembly. Instead, the filter element is simply placed on the central tube, and the housing cover is screwed onto the housing.
In this embodiment it is advantageous to provide a piston rod which extends through the filter element and the liquid cooler into the liquid outlet. This piston rod closes a liquid drain through which, when the piston rod is lifted, the liquid can be drained out without pressure (i.e, under the influence of gravity). When the housing cover is closed, the liquid cooling system is to be ready for operation. In this condition, therefore, the drain must be closed by the piston rod. After the housing cover is removed from the housing the liquid cooling system is no longer ready to operate, and the liquid contained in the filter element and return passage should drain away so that the filter element can be replaced, for example. In order that it will not be necessary to remove the piston rod from the liquid drain, the liquid cooler and the filter element, an axial stop is provided in the liquid outlet for the piston rod to strike against when the cover is removed. Also, the piston rod is releasably snapped into the housing cover. When the liquid cooling system is assembled, the piston rod is inserted into the liquid outlet, then the liquid cooler is screwed in place with the threaded nipple, so that the piston rod can no longer be removed from the liquid drain. After the filter element is inserted the housing cover is placed on the housing, causing the piston rod to engage in a socket provided for it. The piston rod is sealingly pressed against the liquid drain by the housing cover. When the housing cover is removed, a tension force acts on the piston rod which lifts the piston rod from the liquid drain, and then makes it possible for the liquid to drain out through the liquid outlet. To remove the housing cover completely in order to replace the filter element, for example, the piston rod is released from the socket. The socket can be, for example, a releasable catch which permits repeated attachment and release of the piston rod.
It is advantageous that fastening units are provided on the housing for affixing the liquid cooling system to an adjacent component. The fastening units, however, are necessary only when the housing is an independent component and is not formed, for example, by a component present in a vehicle. The fastening units can be in the form of bores through which screws are inserted and can be screwed into a supporting component. Other fastening units such as snap fasteners or clamping elements can likewise be provided.
These and other features of preferred embodiments of the invention, in addition to being set forth in the claims, are also disclosed in the specification and/or the drawings, and the individual features each may be implemented in embodiments of the invention either individually or in the form of subcombinations of two or more features and can be applied to other fields of use and may constitute advantageous, separately protectable constructions for which protection is also claimed.